A short distance radar apparatus may transmit and receive signals using a two-antenna scheme or a single-antenna scheme. For a conventional two-antenna short distance radar apparatus, two antennas are respectively used for transmitting and receiving, resulting in a relatively high hardware cost of the conventional two-antenna short distance radar apparatus. For a conventional single-antenna short distance radar apparatus, a single antenna is used for both transmitting and receiving, and a ferrite circulator is generally used for signal separation. The ferrite circulator cannot be fabricated by standard semiconductor process, resulting in a relatively high hardware cost of the conventional single-antenna short distance radar apparatus.